SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6b4cb38783ea29c2c4c14b4ada2fb383b0a0d1e479aef579a89c3f870a73469' 
  AND token = 'uYbZm/spAJyOxIn+s5whnmKTuo9uksY1/FnbqsR+Ppg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}